Rotor icing is a significant flight safety hazard to helicopters that do not have rotor deicing systems. In manned helicopters, pilots are therefore careful to avoid or quickly exit icing conditions. Helicopter UAVs (unmanned aerial vehicles) are as prone to icing as manned helicopters, but do not have the human pilot's eyes to avoid or quickly detect icing. Commercially available fixed-wing-type ice detectors are slow to sense icing on a helicopter where ice can accrete much faster on rotor blades than on other parts of the airframe. Even small accumulations of rotor ice can quickly lead to loss of control and/or loss of aircraft.